This project will investigate the physiological controls that regulate protein synthesis and secretion in the lacrimal gland. Tears are composed of secretions from several extra-ocular glands; however, by volume most of the tears are secreted by the lacrimal gland. Tears contain many proteins that have anti-infective and other properties. Poorly functioning lacrimal glands are associated with "dry eye" syndromes which may be painful and increase the risk of eye infections and loss of corneal clarity. Secretion of proteins is under autonomic control in both human and rabbit lacrimal glands. This project will use rabbit lacrimal glands as a model for investigating the relationship between protein secretion and restitution of the secreted proteins by de novo synthesis. Fragments of rabbit lacrimal gland will be incubated in vitro. The tissue will be stimulated to secrete proteins into the incubation medium. After 20 min of secretion the tissue will be transferred to a maintenance medium for 1 hr. At hourly intervals thereafter some tissue fragments will be placed in a medium containing 3H-leucine. After 45 min, the tissue will be collected and homogenized and the amount of protein synthesized will be determined by the amount of 3H-leucine found in the protein. By this technique several variables can be investigated to determine their role in protein synthesis. Protein secretion will be elicited by the parasympathomimetic drug carbamylcholine, the sympathomimetic drug 1-isoproterenol HC1, high concentrations of extracellular KC1, Ca++ influx and cAMP synthesis. The electrophoretic pattern of newly synthesized proteins will be visualized by autofluorography of the incorporated 3H-leucine. The effect of surgical sympathectomy on protein secretion and synthesis will also be determined. The long-term objective for this project is to develop an understanding of the normal physiological control mechanisms which regulate protein secretion and synthesis. Since all of the functions of the lacrimal gland are under control of the autonomic nervous system, an understanding of protein secretion and synthesis may lead to better treatment protocol for dry eyes and related lacrimal disfunctions.